Wireless power transmission system, and method of controlling transmission and reception of resonance power

ABSTRACT

A resonance power transmission system, and a method of controlling transmission and reception of a resonance power are provided. According to one embodiment, a method of controlling resonance power transmission in a resonance power transmitter may include: transmitting resonance power to a resonance power receiver, the resonance power having resonance frequencies which vary with respect to a plurality of time intervals; and receiving, from the resonance power receiver, information regarding the resonance frequency having the highest power transmission efficiency among the resonance frequencies used in the time intervals.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.13/293,435, filed Nov. 10, 2011, which claims the benefit under 35U.S.C. §119(a) of Korean Patent Application No. 10-2010-0111304, filedon Nov. 10, 2010, in the Korean Intellectual Property Office, the entiredisclosure of which is incorporated herein by reference for allpurposes.

BACKGROUND

1. Field

The following description relates to wireless power transmission.

2. Description of Related Art

Resonance power refers to a type of electromagnetic energy that iswirelessly transmitted. A typical resonance power transmission systemincludes a source electronic device and a target electronic device. Theresonance power may be transferred from the source electronic device tothe target electronic device. More particularly, the source electronicdevice may transmit resonance power, and the target electronic devicemay receive the resonance power. The source electronic device and thetarget electronic device may be referred to as a resonance powertransmitter and a resonance power receiver, respectively.

Due to characteristics of a wireless environment, the distance between asource resonator and a target resonator may be highly likely to varyover time, and matching requirements to match the source resonator andthe target resonator may also change.

SUMMARY

According to one aspect, a method of controlling resonance powertransmission in a resonance power transmitter may include: transmittingresonance power to a resonance power receiver, the resonance powerhaving resonance frequencies which vary with respect to a plurality oftime intervals; and receiving, from the resonance power receiver,information regarding the resonance frequency having a highest powertransmission efficiency among the resonance frequencies used in the timeintervals.

The method may further include: detecting the resonance power receiver.The detecting may include: receiving an identifier (ID) of the resonancepower receiver; and recognizing the resonance power receiver based onthe received ID.

The method may further include: notifying the resonance power receiverof the resonance frequencies used in the time intervals, and of a poweramount of the resonance power transmitted in one or more of the timeintervals.

The method my further include: generating the resonance power using theresonance frequency having the highest power transmission efficiency;and transmitting the generated resonance power to the resonance powerreceiver.

One or more of the resonance frequencies used in the time intervals maybe determined by scanning a frequency characteristic of a reflectedwave, determined based on a channel of a predetermined width, orrandomly determined in a predetermined bandwidth.

The time intervals may include preset or predetermined time intervals.

According to another aspect, a method of controlling resonance powertransmission in a resonance power transmitter may include: determiningan order of a plurality of resonance power receivers; transmitting firstresonance power to a first resonance power receiver of the plurality ofresonance power receivers based on the determined order, the firstresonance power having resonance frequencies which vary for a pluralityof time intervals;

receiving a first resonance frequency from the first resonance powerreceiver, the first resonance frequency having the highest powertransmission efficiency for the first resonance power receiver amongresonance frequencies used in the time intervals; transmitting secondresonance power to a second resonance power receiver of the plurality ofresonance power receivers based on the determined order, the secondresonance power having a resonance frequency variable for of timeintervals; and receiving a second resonance frequency from the secondresonance power receiver, the second resonance frequency having thehighest power transmission efficiency for the second resonance powerreceiver among the resonance frequencies used in the time intervals.

The method may further include: detecting the plurality of resonancepower receivers.

The method may further include: generating the first resonance powerusing the first resonance frequency, and transmitting the firstresonance power generated using the first resonance frequency to thefirst resonance power receiver in a first time interval; and generatingthe second resonance power using the second resonance frequency, andtransmitting the second resonance power generated using the secondresonance frequency to the second resonance power receiver in a secondtime interval.

The method may further include: generating the first resonance powerusing the first resonance frequency, and transmitting the firstresonance power generated using the first resonance frequency to thefirst resonance power receiver; determining whether charging of thefirst resonance power receiver is completed; and generating the secondresonance power using the second resonance frequency, and transmittingthe second resonance power generated using the second resonancefrequency to the second resonance power receiver, when the charging ofthe first resonance power receiver is completed.

The method may further include: generating the first resonance powerusing the first resonance frequency, and transmitting the firstresonance power generated using the first resonance frequency to thefirst resonance power receiver; determining whether a report message isreceived from the first resonance power receiver within a predeterminedperiod of time; and generating the second resonance power using thesecond resonance frequency, and transmitting the second resonance powergenerated using the second resonance frequency to the second resonancepower receiver, when the report message is not received within thepredetermined period of time.

One or more of the resonance frequencies used in the time intervals maybe determined by scanning a frequency characteristic of a reflectedwave, determined based on a channel of a predetermined width, orrandomly determined in a predetermined bandwidth.

According to yet another aspect, a method of controlling resonance powerreception in a resonance power receiver may include: receiving resonancepower from the resonance power transmitter, the resonance power havingresonance frequencies which vary for a plurality of time intervals;receiving information regarding resonance frequencies used in the timeintervals; detecting a resonance frequency having the highest powertransmission efficiency among the resonance frequencies used in the timeintervals; and notifying the resonance power transmitter of the detectedresonance frequency.

The method may further include: receiving, from the resonance powertransmitter, resonance power generated using the detected resonancefrequency.

The method may further include: determining whether charging of theresonance power receiver is completed; and notifying the resonance powertransmitter of a completion of the charging of the resonance powerreceiver, when the charging of the resonance power receiver iscompleted.

According to still another aspect, a resonance power transmitter mayinclude: a resonance power generator configured to generate theresonance power, wherein resonance frequencies of the resonance powervary for a plurality of time intervals; and a source resonatorconfigured to transmit the resonance power to a resonance powerreceiver; a communication unit configured to receive, from the resonancepower receiver, information regarding the resonance frequency having thehighest power transmission efficiency among the resonance frequenciesused in the time intervals.

The resonance power transmitter may further include: a detectorconfigured to detect the resonance power receiver.

The resonance power generator may be configured to generate theresonance power using the resonance frequency having the highest powertransmission efficiency, and the source resonator may be configured totransmit the generated resonance power to the resonance power receiver.

One or more of the resonance frequencies used in the time intervals maybe determined by scanning a frequency characteristic of a reflectedwave, determined based on a channel of a predetermined width, orrandomly determined in a predetermined bandwidth.

According to a further aspect, a resonance power receiver may include: atarget resonator configured to receive resonance power from a resonancepower transmitter, the resonance power having resonance frequencieswhich vary for a plurality of time intervals; a communication unitconfigured to receive information regarding the resonance frequenciesused in the time intervals; and a target controller configured to detecta resonance frequency having the highest power transmission efficiencyamong the resonance frequencies used in the time intervals, wherein thecommunication unit is configured to transmit the detected resonancefrequency to the resonance power transmitter.

The target resonator may be configured to receive, from the resonancepower transmitter, resonance power generated using the detectedresonance frequency.

When charging of the resonance power receiver is completed, the targetcontroller may be configured to notify the resonance power transmitterof a completion of the charging of the resonance power receiver.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a resonance power transmitter.

FIG. 2 is a diagram illustrating a resonance power receiver.

FIG. 3 is a diagram illustrating an environment in which a plurality ofresonance power receivers exist.

FIG. 4 is a diagram illustrating a resonance power transmission system.

FIG. 5 is a diagram illustrating another resonance power transmissionsystem.

FIG. 6 is a diagram illustrating data transmitted from the resonancepower transmitter of FIG. 1.

FIG. 7 is a diagram illustrating data transmitted from the resonancepower receiver of FIG. 2.

FIG. 8 is a diagram illustrating frequency hopping.

FIG. 9 is a diagram illustrating a frequency spectrum with respect to atransmitted power and a reflected power.

FIG. 10 is a diagram illustrating a method of controlling resonancepower transmission in a resonance power transmitter.

FIG. 11 is a diagram illustrating another method of controllingresonance power transmission in a resonance power transmitter.

FIG. 12 is a diagram illustrating still another method of controllingresonance power transmission in a resonance power transmitter.

FIG. 13 is a diagram illustrating yet another method of controllingresonance power transmission in a resonance power transmitter.

FIGS. 14 and 15 are diagrams illustrating power transmission in a timedomain.

FIGS. 16 through 22B are diagrams illustrating various resonatorstructures.

FIG. 23 is a diagram illustrating one equivalent circuit of theresonator of FIG. 16.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. Accordingly, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be suggested to those of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Also, description of well-known functions andconstructions may be omitted for increased clarity and conciseness.

FIGS. 1 and 2 illustrate a resonance power transmitter 100 and aresonance power receiver 200, respectively, which together may form awireless power transmission system.

FIG. 1 illustrates the resonance power transmitter 100. As shown in FIG.1, the resonance power transmitter 100 may include a source resonator110, a detector 120, a resonance power generator 130, a sourcecontroller 140, a communication unit 150 a rectifier 160, and a constantvoltage controller 170.

FIG. 2 illustrates the resonance power receiver 200. As shown in FIG. 2,the resonance power receiver 200 may include a target resonator 210, acommunication unit 220, a target controller 230 a rectifier 240, adirect current (DC)-to-DC (DC/DC) converter 250, and a load 260.

The source resonator 110 may be configured to transfer electromagneticenergy to the target resonator 210. For example, the source resonator110 may transfer a resonance power to the resonance power receiver 200,through magnetic coupling with the target resonator 210. The sourceresonator 110 may resonate within a set resonance bandwidth.

The detector 120 may be configured to detect the resonance powerreceiver 200. For example, the detector 120 may detect the resonancepower receiver 200, based on an identifier (ID) of the resonance powerreceiver 200 received from the resonance power receiver 200, forinstance. When a resonance power needs to be received, the resonancepower receiver 200 may transmit the ID to the resonance powertransmitter 100. And, when the ID is received, the detector 120 maydetermine that the resonance power receiver 200 exists.

The resonance power generator 130 may be configured to generateresonance power under a control of the source controller 140. Forinstance, the resonance power generator 130 may convert a DC voltage ofa predetermined level to an alternating current (AC), by a switchingpulse signal (e.g., in a band of one or more megahertz (MHz) to tens ofMHz). In some embodiments, the resonance power generator 130 may includean AC-to-DC (AC/DC) inverter. The DC voltage of the predetermined levelmay be provided from the constant voltage controller 170. The AC/DCinverter may include a switching device for high-speed switching, forinstance. When the switching pulse signal is “high” (i.e., at or nearits maximum), the switching device may be powered “ON.” And when theswitching pulse signal is “low” (i.e., at or near its minimum) theswitching device may be powered “OFF.”

The resonance power generator 130 may generate a resonance power, underthe control of the source controller 140. The resonance power may have aresonance frequency which may vary for one or more time intervals. Thetime intervals may be preset or predetermined, for example.Additionally, under the control of the source controller 140, theresonance power generator 130 may generate the resonance power using theresonance frequency having the highest power transmission efficiencyamong a plurality of resonance frequencies for the time intervals. Thesource resonator 110 may transmit, to the resonance power receiver 200,the resonance power generated using the resonance frequency having thehighest power transmission efficiency.

The source controller 140 may be configured to control the resonancepower generator 130, so that the resonance frequency of the resonancepower generated by the resonance power generator 130 may vary for one ormore of the time intervals. Additionally, the source controller 140 maycontrol an overall operation of the resonance power transmitter 100. Thesource controller 140 may be configured to control an operation of atleast one of the detector 120, the resonance power generator 130, thecommunication unit 150, and the constant voltage controller 170. One ormore of resonance frequencies used respectively in the time intervalsmay be determined by scanning a frequency characteristic of a reflectedwave, or may be determined based on a channel with a predeterminedwidth, or may be randomly determined in a predetermined bandwidth.

In some embodiments, the source controller 140 may include a frequencyanalyzer 141, a frequency scanning table 143, and a processor 145, asillustrated in FIG. 1.

The frequency analyzer 141 may be configured to determine the resonancefrequencies used respectively in the time intervals, through analysis ofa frequency spectrum illustrated in FIG. 9. In a situation where afrequency spectrum is measured in a time interval T1, as illustrated inFIG. 9, the frequency analyzer 141 may determine a resonance frequencyused in the time interval T1 to be a frequency “F₁” or “F₂.” FIG. 9illustrates one example of a frequency spectrum with respect to atransmitted power and a reflected power. In FIG. 9, “n21” represents afrequency spectrum for the transmitted power, and “n11” represents afrequency spectrum for the reflected power. In some instances, thereflected power may be measured by a reflected signal coupler.

The frequency scanning table 143 may record or otherwise store resonancefrequencies that are variable based on a channel of a predeterminedwidth, record resonance frequencies that are randomly variable, or both.

The processor 145 may be configured to manage and/or control functionsof the source controller 140.

The communication unit 150 may transmit, to the resonance power receiver200, the resonance frequencies used in the time intervals, and a poweramount of a resonance power transmitted in one or more of the timeintervals, under the control of the source controller 140. Additionally,the communication unit 150 may receive, from the resonance powerreceiver 200, the resonance frequency having the highest powertransmission efficiency among the resonance frequencies usedrespectively in the time intervals.

The communication unit 150 may perform an in-band communication fortransmitting or receiving data to or from the resonance power receiver200 via a resonance frequency, and may perform an out-band communicationfor transmitting or receiving data to or from the resonance powerreceiver 200 via a frequency assigned for data communication.

The term “in-band” communication(s), as used herein, meanscommunication(s) in which information (such as, for example, controlinformation, data and/or metadata) is transmitted in the same frequencyband, and/or on the same channel, as used for power transmission.According to one or more embodiments, the frequency may be a resonancefrequency. And, the term “out-band” communication(s), as used herein,means communication(s) in which information (such as, for example,control information, data and/or metadata) is transmitted in a separatefrequency band and/or using a separate or dedicated channel, than usedfor power transmission.

The rectifier 160 may generate a DC voltage by rectifying an AC voltage(e.g., in a band of tens of Hz).

The constant voltage controller 170 may receive an input of the DCvoltage from the rectifier 160, and may output a DC voltage of apredetermined level under the control of the source controller 140. Theconstant voltage controller 170 may include a stabilization circuit tooutput a DC voltage of a predetermined level, for instance.

The target resonator 210 may receive the electromagnetic energy from thesource resonator 110. For example, the target resonator 210 may receiveresonance power from the resonance power transmitter 100, through themagnetic coupling with the source resonator 110. The target resonator210 may resonate within the set resonance bandwidth.

The communication unit 220 may transmit or receive data to or from thecommunication unit 150, under a control of the target controller 230.For example, the communication unit 220 may transmit the ID of theresonance power receiver 200 to the resonance power transmitter 100.Additionally, the communication unit 220 may receive informationregarding the resonance frequencies used in the time intervals, andinformation on the power amount of the resonance power transmitted inone or more of the time intervals. Furthermore, the communication unit220 may transmit, to the resonance power transmitter 100, the resonancefrequency having the highest power transmission efficiency among theresonance frequencies used respectively in the time intervals. Similarlyto the communication unit 150 in the resonance power transmitter 100,the communication unit 220 may perform the in-band communication and theout-band communication.

The target controller 230 may detect the resonance frequency having thehighest power transmission efficiency among the resonance frequenciesused in the time intervals.

Table 1, below, shows power amounts P1, P2, P3, and P4 of resonancepowers received respectively in time intervals T1, T2, T3, and T4, andpieces of data received from the resonance power transmitter 100. Itshould be appreciated that the specific values shown in Table 1 aremerely an example and that other values are possible. The targetcontroller 230 may detect a frequency F3 as the resonance frequencyhaving the highest power transmission efficiency.

TABLE 1 T1 T2 T3 T4 Used resonance F1 F2 F3 F4 frequency (13.56 MHz)(13.65 MHz) (13.60 MHz) (13.56 MHz) Amount of 100 watt (W) 100 W 100 W100 W resonance power transmitted Amount of P1 (80 W) P2 (85 W) P3 (92W) P4 (90 W) resonance power received

The target controller 230 may be configured to control or otherwisedirect the communication unit 220 to transmit, to the resonance powertransmitter 100, the resonance frequency having the highest powertransmission efficiency among the resonance frequencies usedrespectively in the time intervals. Under the control of the targetcontroller 230, the communication unit 220 may transmit, to theresonance power transmitter 100, the resonance frequency having thehighest power transmission efficiency among the resonance frequenciesused respectively in the time intervals. Accordingly, the targetresonator 210 may receive, from the resonance power transmitter 100, aresonance power generated using the resonance frequency having thehighest power transmission efficiency.

The target controller 230 may include a received power scanning unit231, and a processor 233. The received power scanning unit 231 maymeasure a power amount of a resonance power received in one or more ofthe time intervals. The processor 233 may be configured to manage and/orcontrol functions of the target controller 230.

The rectifier 240 may generate a DC voltage by rectifying an AC voltage.

The DC/DC converter 250 may adjust a level of the DC voltage output fromthe rectifier 240, and may provide a DC voltage required by the load260.

The load 260 may include a charge battery to supply a power required bythe resonance power receiver 200 and to charge the resonance powerreceiver 200. The target controller 230 may monitor the load 260, andmay notify the resonance power transmitter 100 of a completion ofcharging of the resonance power receiver 200 when the charging of theresonance power receiver 200 is completed.

FIG. 3 illustrates an environment in which a plurality of resonancepower receivers exist.

As illustrated in FIG. 3, the resonance power transmitter 100 maytransmit a resonance power to a plurality of resonance power receivers200 a, 200 b, and 200 c. The environment where the resonance powerreceivers 200 a, 200 b, and 200 c exist may be referred to as a “1-to-Ncharging environment”. In the 1-to-N charging environment, powertransmission efficiency may be reduced when the resonance powerreceivers 200 a, 200 b, and 200 c interfere with each other, when one ofthe resonance power receivers 200 a, 200 b, and 200 c is removed, and/orwhen a new device is added. Accordingly, there is provided a method ofcontrolling resonance power transmission based on each of the resonancepower receivers 200 a, 200 b, and 200 c. Reference numerals 301, 303,305, and 307 of FIG. 3 represent magnetic coupling between adjacentresonators.

FIG. 4 illustrates a resonance power transmission system.

Referring to FIG. 4, the resonance power transmitter 100 may transmit,to the resonance power receivers 200 a, 200 b, and 200 c, a resonancepower with resonance frequencies F1, F2, and FN that are sequentiallyvariable.

The resonance power transmitter 100 may determine an order of theresonance power receivers 200 a, 200 b, and 200 c, and may transmit, tothe resonance power receiver 200 a, a resonance power with resonancefrequencies F1, F2, and FN that are sequentially variable in operation410. After receiving a first response from the resonance power receiver200 a, the resonance power transmitter 100 may transmit, to theresonance power receiver 200 b, a resonance power with resonancefrequencies F1, F2, and FN that are sequentially variable in operation420. The first response may include information on a resonance frequencyhaving a highest power transmission efficiency among the resonancefrequencies F1, F2, and FN. Additionally, the first response may furtherinclude an ID of the resonance power receiver 200 a.

After receiving a second response from the resonance power receiver 200b, the resonance power transmitter 100 may transmit, to the resonancepower receiver 200 c, a resonance power with resonance frequencies F1,F2, and FN that are sequentially variable in operation 430. The secondresponse may include information on a resonance frequency having ahighest power transmission efficiency among the resonance frequenciesF1, F2, and FN. Additionally, the second response may further include anID of the resonance power receiver 200 b.

In FIG. 4, it may assumed that, the resonance frequency having thehighest power transmission efficiency for the resonance power receiver200 a is denoted by “Fs1”, and that the resonance frequency having thehighest power transmission efficiency for the resonance power receiver200 b is denoted by “Fs2.” The resonance frequencies Fs1 and Fs2 may bedifferent from, or identical to each other. Operations 410 through 430of FIG. 4 may be performed sequentially or simultaneously, in someinstances. In a situation where operations 410 through 430 aresimultaneously performed, the resonance power transmitter 100 mayidentify the resonance power receivers 200 a, 200 b, and 200 c, based onthe IDs of the resonance power receivers 200 a, 200 b, and 200 c.

FIG. 5 illustrates another resonance power transmission system.

Referring to FIG. 5, the resonance power transmitter 100 may transmit aresonance power with a resonance frequency F1 to a resonance powerreceiver 200 a in operation 510. Similarly to the transmitter of FIG. 4,the resonance power transmitter 100 may receive a response signal fromthe resonance power receiver 200 a, and may transmit another resonancepower with the resonance frequency F1 to a resonance power receiver 200b in operation 520. Similarly, the resonance power transmitter 100 mayreceive a response signal from the resonance power receiver 200 b andmay transmit another resonance power with the resonance frequency F1 toa resonance power receiver 200 c in operation 530. One or more of theresponse signals may include information regarding the efficiency ofreceiving a resonance power with a resonance frequency F1 or an amountof resonance power received in the resonance frequency F1. Additionally,one or more of the response signals may further include an ID of acorresponding resonance power receiver. When responding to the resonancefrequency F1 is completed, the resonance power transmitter 100 mayperform operations 510 through 530 with respect to a resonance frequencyF2.

FIG. 6 illustrates data transmitted from the resonance power transmitter100 of FIG. 1.

Referring to FIG. 6, the resonance power transmitter 100 maysimultaneously transmit data 610 and a resonance power with a resonancefrequency F1 to the resonance power receiver 200 of FIG. 2 in a timeinterval t1. The data 610 may include information on the resonancefrequency F1 used to generate the resonance power, and/or information ona power amount of the resonance power, as illustrated in FIG. 6.Reference numeral 620 of FIG. 6 represents data transmitted to theresonance power receiver 200 in a time interval t2.

FIG. 7 illustrates data transmitted from the resonance power receiver200 of FIG. 2.

Referring to FIG. 7, the resonance power receiver 200 may detect data720 regarding amounts of power received respectively corresponding toresonance frequencies F1, F2, . . . , and FN, and may compute anefficiency corresponding to each of the resonance frequencies F1, F2, .. . , and FN. In FIG. 7, data 710 for resonance frequency F3 may have ahighest power transmission efficiency among the resonance frequenciesF1, F2, and FN. The resonance power receiver 200 may transmit, to theresonance power transmitter 100 of FIG. 1, the efficiency computed foreach of the resonance frequencies F1, F2, and FN, individually. Or theresonance power receiver 200 may transmit the data 720 to the resonancepower transmitter 100, instead of computing the efficiency correspondingto each of the resonance frequencies F1, F2, and FN.

FIG. 8 illustrates frequency hopping.

In FIG. 8, resonance frequencies used to transmit resonance powers maybe randomly hopped or skipped. For example, resonance frequencies F1,F3, and F6 may sequentially determine, instead of resonance frequenciesF1, F2, and FN being sequentially determined. In operation 810, aresonance power transmitter may transmit resonance power to a resonancepower receiver using a resonance frequency F1. Additionally, inoperation 810, the resonance power transmitter may transmit, to theresonance power receiver, information on the resonance frequency F1 andinformation on a power amount. Operation 820 may be performed withrespect to a reference frequency F3, in a similar manner as operation810. Additionally, operation 840 may be performed with respect to areference frequency F6, in a similar manner as operation 810. Inoperation 830, the resonance power receiver may transmit, to theresonance power transmitter, information on a power transmissionefficiency or information on an amount of power received.

FIG. 10 illustrates a method of controlling resonance power transmissionin a resonance power transmitter. In one or more embodiments, the methodof FIG. 10 may be performed by the resonance power transmitter 100 ofFIG. 1.

In operation 1010, the resonance power transmitter 100 may detect aresonance power receiver. For example, the resonance power transmitter100 may determine whether a resonance power receiver exists within acoverage that enables the resonance power transmission. The resonancepower transmitter 100 may receive an ID of the resonance power receiver,and may recognize the resonance power receiver based on the received ID.

In operation 1020, the resonance power transmitter 100 may transmitresonance power to the detected resonance power receiver. The resonancefrequency of the resonance power transmitted in operation 1020 may varyfor one or more of time intervals. One or more of the resonancefrequencies used in the time intervals may be determined by scanning afrequency characteristic of a reflected wave, or may be determined basedon a channel of a predetermined width, or may be randomly determined ina predetermined bandwidth.

In operation 1030, the resonance power transmitter 100 may notify thedetected resonance power receiver of the resonance frequencies usedrespectively in the time intervals, and of a power amount of theresonance power transmitted in each of the time intervals. The detectedresonance power receiver may detect a resonance frequency having thehighest power transmission efficiency among the resonance frequenciesused respectively in the time intervals, and may notify the resonancepower transmitter 100 of the detected resonance frequency.

In operation 1040, the resonance power transmitter 100 may receive thedetected resonance frequency from the detected resonance power receiver.

In operation 1050, the resonance power transmitter 100 may generate theresonance power using the resonance frequency received in operation1040.

In operation 1060, the resonance power transmitter 100 may transmit theresonance power generated in operation 1050 to the resonance powerreceiver.

FIG. 11 illustrates another method of controlling resonance powertransmission in a resonance power transmitter.

In one or more embodiments, the method of FIG. 11 may be performed usingthe resonance power transmitter 100 of FIG. 1.

In operation 1110, the resonance power transmitter 100 may detect aplurality of resonance power receivers. For example, the resonance powertransmitter 100 may receive IDs of the plurality of resonance powerreceivers, and may recognize the plurality of resonance power receiverbased on the received IDs. Accordingly, the resonance power transmitter100 may verify a number of resonance power receivers based on a numberof the received IDs.

In operation 1120, the resonance power transmitter 100 may determine anorder of the plurality of resonance power receivers detected inoperation 1110. This may be the sequential order in which they weredetected, in some instances. Alternatively, some predetermined ordefault ordering system might be employed.

In operation 1130, the resonance power transmitter 100 may transmitresonance power to a first resonance power receiver based on thedetermined order. The resonance frequency of the resonance powertransmitted in operation 1130 may vary for each of time intervals.

In operation 1140, the resonance power transmitter 100 may receive, fromthe first resonance power receiver, a resonance frequency Fs1 having ahighest power transmission efficiency for the first resonance powerreceiver among resonance frequencies used respectively in the timeintervals.

In operation 1150, the resonance power transmitter 100 may transmitresonance power to a second resonance power receiver based on thedetermined order. The resonance frequency of the resonance powertransmitted in operation 1150 may vary for each of the time intervals.

In operation 1160, the resonance power transmitter 100 may receive, fromthe second resonance power receiver, a resonance frequency Fs2 having ahighest power transmission efficiency for the second resonance powerreceiver among the resonance frequencies used respectively in the timeintervals.

In operation 1170, the resonance power transmitter 100 may generate theresonance power using the resonance frequency Fs1, and may transmit theresonance power generated using the resonance frequency Fs1 to the firstresonance power receiver in a first time interval.

In operation 1180, the resonance power transmitter 100 may generate theresonance power using the resonance frequency Fs2, and may transmit theresonance power generated using the resonance frequency Fs2 to thesecond resonance power receiver in a second time interval.

FIG. 12 illustrates still another method of controlling resonance powertransmission in a resonance power transmitter.

In some instances, operations 1210 through 1260 of FIG. 12 may besimilar to operations 1110 through 1160 of FIG. 11 and accordingly,further descriptions of operation 1210 through 1260 will be omitted.

In operation 1270, the resonance power transmitter 100 may generate theresonance power using the resonance frequency Fs1, and may transmit theresonance power generated using the resonance frequency Fs1 to the firstresonance power receiver.

In operation 1280, the resonance power transmitter 100 may determinewhether charging of the first resonance power receiver is completed. Forexample, whether the charging of the first resonance power receiver iscompleted may be determined based on whether a message indicating acompletion of the charging is received from the first resonance powerreceiver.

If charging of the first resonance power receiver is not completed, themethod returns to operation 1270. And, when the charging of the firstresonance power receiver is completed, the resonance power transmitter100 may generate the resonance power using the resonance frequency Fs2,and may transmit the resonance power generated using the resonancefrequency Fs2 to the second resonance power receiver in operation 1290.

FIG. 13 illustrates yet another method of controlling resonance powertransmission in a resonance power transmitter.

In some instance, operations 1310 through 1360 of FIG. 13 may be similarto operations 1110 through 1160 of FIG. 11 and accordingly, furtherdescriptions of operation 1310 through 1360 will be omitted.

In operation 1370, the resonance power transmitter 100 may generate theresonance power using the resonance frequency Fs1, and may transmit theresonance power generated using the resonance frequency Fs1 to the firstresonance power receiver.

In operation 1380, the resonance power transmitter 100 may determinewhether a report message is received from the first resonance powerreceiver within a predetermined period of time. The first resonancepower receiver may notify the resonance power transmitter 100 that thefirst resonance power receiver continues to be charged by periodicallytransmitting report messages to the resonance power transmitter 100.Accordingly, when a report message is not received from the firstresonance power receiver within the predetermined period of time, theresonance power transmitter 100 may determine or assume that the firstresonance power receiver does not exist. The report message may includean ID of the first resonance power receiver, for instance.

If the report message is received from the first resonance powerreceiver within the predetermined period of time, the method returns tooperation 1370. And when the report message is not received from thefirst resonance power receiver within the predetermined period of time,the resonance power transmitter 100 may terminate transmitting theresonance power to the first resonance power receiver. Additionally, theresonance power transmitter 100 may generate the resonance power usingthe resonance frequency Fs2, and may transmit the resonance powergenerated using the resonance frequency Fs2 to the second resonancepower receiver in operation 1390.

FIGS. 14 and 15 illustrate resonance power transmission, after resonancefrequencies Fs1 and Fs2 are received from resonance power receivers 200a and 200 b.

In FIG. 14, the resonance power transmitter 100 may transmit a resonancepower to the resonance power receiver 200 a using the resonancefrequency Fs1 in a first time interval 1410, and may transmit aresonance power to the resonance power receiver 200 b using theresonance frequency Fs2 in a second time interval 1420. The resonancepower transmitter 100 may generate the resonance power by alternatelyusing the resonance frequencies Fs1 and Fs2.

In FIG. 15, the resonance power transmitter 100 may transmit resonancepower to the resonance power receiver 200 a using the resonancefrequency Fs1 in a third time interval 1510 and a fourth time interval1520. Thus, for consecutive time intervals, the resonance frequency Fs1having a highest power transmission efficiency for the resonance powerreceiver 200 a may be used, as illustrated in FIG. 15.

According to various example embodiments, it may be possible toefficiently manage resonance frequencies in a resonance frequency band.

Additionally, it may be possible to efficiently charge a plurality ofelectronic devices with a resonance power, by managing resonancefrequencies respectively corresponding to the plurality of electronicdevices. Furthermore, high-efficiency wireless power transmission may beperformed by selecting a resonance frequency with high powertransmission efficiency.

Referring again to FIGS. 1 and 2, the source resonator 110 and/or thetarget resonator 210 may be configured, for example, as a helix coilstructured resonator, a spiral coil structured resonator, ameta-structured resonator, and/or the like.

An electromagnetic characteristic of many materials found in nature isthat they have a unique magnetic permeability or a unique permittivity.Most materials typically have a positive magnetic permeability or apositive permittivity. Thus, for these materials, a right hand rule maybe applied to an electric field, a magnetic field, and a pointing vectorand thus, the corresponding materials may be referred to as right handedmaterials (RHMs).

On the other hand, a material having a magnetic permeability or apermittivity which is not ordinarily found in nature or isartificially-designed (or man-made) may be referred to herein as a“metamaterial.” Metamaterials may be classified into an epsilon negative(ENG) material, a mu negative (MNG) material, a double negative (DNG)material, a negative refractive index (NRI) material, a left-handed (LH)material, and the like, based on a sign of the correspondingpermittivity or magnetic permeability.

The magnetic permeability may indicate a ratio between a magnetic fluxdensity occurring with respect to a predetermined magnetic field in acorresponding material and a magnetic flux density occurring withrespect to the predetermined magnetic field in a vacuum state. Thepermittivity indicates a ratio between an electric flux densityoccurring with respect to a given electric field in a correspondingmaterial and an electric flux density occurring with respect to thegiven electric field in a vacuum state. The magnetic permeability andthe permittivity, in some embodiments, may be used to determine apropagation constant of a corresponding material in a predeterminedfrequency or a predetermined wavelength. An electromagneticcharacteristic of the corresponding material may be determined based onthe magnetic permeability and the permittivity. According to an aspect,the metamaterial may be easily disposed in a resonance state withoutsignificant material size changes. This may be practical for arelatively large wavelength area or a relatively low frequency area.

FIG. 16 is an illustration of a two-dimensional (2D) resonator 1600.

As shown, the resonator 1600 having the 2D structure may include atransmission line, a capacitor 1620, a matcher 1630, and conductors 1641and 1642. The transmission line may include, for instance, a firstsignal conducting portion 1611, a second signal conducting portion 1612,and a ground conducting portion 1613.

The capacitor 1620 may be inserted or otherwise positioned in seriesbetween the first signal conducting portion 1611 and the second signalconducting portion 1612 so that an electric field may be confined withinthe capacitor 1620, as illustrated in FIG. 16. In variousimplementations, the transmission line may include at least oneconductor in an upper portion of the transmission line, and may alsoinclude at least one conductor in a lower portion of the transmissionline. A current may flow through the at least one conductor disposed inthe upper portion of the transmission line and the at least oneconductor disposed in the lower portion of the transmission may beelectrically grounded. As illustrated in FIG. 16, the resonator 1600 maybe configured to have a generally 2D structure. The transmission linemay include the first signal conducting portion 1611 and the secondsignal conducting portion 1612 in the upper portion of the transmissionline, and may include the ground conducting portion 1613 in the lowerportion of the transmission line. As shown, the first signal conductingportion 1611 and the second signal conducting portion 1612 may bedisposed to face the ground conducting portion 1613 with current flowingthrough the first signal conducting portion 1611 and the second signalconducting portion 1612.

In some implementations, one end of the first signal conducting portion1611 may be electrically connected (i.e., shorted) to the conductor1642, and another end of the first signal conducting portion 1611 may beconnected to the capacitor 1620. And one end of the second signalconducting portion 1612 may be grounded to the conductor 1641, andanother end of the second signal conducting portion 1612 may beconnected to the capacitor 1620. Accordingly, the first signalconducting portion 1611, the second signal conducting portion 1612, theground conducting portion 1613, and the conductors 1641 and 1642 may beconnected to each other such that the resonator 1600 may have anelectrically “closed-loop structure.” The term “closed-loop structure”as used herein, may include a polygonal structure, for example, acircular structure, a rectangular structure, or the like that is acircuit that is electrically closed.

The capacitor 1620 may be inserted into an intermediate portion of thetransmission line. For example, the capacitor 1620 may be inserted intoa space between the first signal conducting portion 1611 and the secondsignal conducting portion 1612. The capacitor 1620 may be configured, insome instances, as a lumped element, a distributed element, or the like.In one implementation, a distributed capacitor may be configured as adistributed element and may include zigzagged conductor lines and adielectric material having a relatively high permittivity between thezigzagged conductor lines.

If the capacitor 1620 is inserted into the transmission line, theresonator 1600 may have a property of a metamaterial, as discussedabove. For example, the resonator 1600 may have a negative magneticpermeability due to the capacitance of the capacitor 1620. If so, theresonator 1600 may also be referred to as a mu negative (MNG) resonator.Various criteria may be applied to determine the capacitance of thecapacitor 1620. For example, the various criteria for enabling theresonator 1600 to have the characteristic of the metamaterial mayinclude one or more of the following: a criterion to enable theresonator 1600 to have a negative magnetic permeability in a targetfrequency, a criterion to enable the resonator 1600 to have a zerothorder resonance characteristic in the target frequency, or the like. Theresonator 1600, also referred to as the MNG resonator 1600, may alsohave a zeroth order resonance characteristic (i.e., having, as aresonance frequency, a frequency when a propagation constant is “0”). Ifthe resonator 1600 has the zeroth order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 1600. Moreover, by appropriately designing thecapacitor 1620, the MNG resonator 1600 may sufficiently change theresonance frequency without significantly changing the physical size ofthe MNG resonator 1600.

In a near field, for instance, the electric field may be concentrated onthe capacitor 1620 inserted into the transmission line. Accordingly, dueto the capacitor 1620, the magnetic field may become dominant in thenear field. In one or more embodiments, the MNG resonator 1600 may havea relatively high Q-factor using the capacitor 1620 of the lumpedelement. Thus, it may be possible to enhance power transmissionefficiency. For example, the Q-factor indicates a level of an ohmic lossor a ratio of a reactance with respect to a resistance in the wirelesspower transmission. The efficiency of the wireless power transmissionmay increase according to an increase in the Q-factor.

The MNG resonator 1600 may include a matcher 1630 to be used inimpedance matching. For example, the matcher 1630 may be configured toappropriately determine and adjust the strength of a magnetic field ofthe MNG resonator 1600. Depending on the configuration, current may flowin the MNG resonator 1600 via a connector, or may flow out from the MNGresonator 1600 via the connector. The connector may be connected to theground conducting portion 1613 or the matcher 1630. In some instances,the power may be transferred through coupling without using a physicalconnection between the connector and the ground conducting portion 1613or the matcher 1630.

As illustrated in FIG. 16, the matcher 1630 may be positioned within theloop formed by the loop structure of the resonator 1600. The matcher1630 may adjust the impedance of the resonator 1600 by changing thephysical shape of the matcher 1630. For example, the matcher 1630 mayinclude the conductor 1631 to be used in the impedance matchingpositioned in a location that is separate from the ground conductingportion 1613 by a distance h. The impedance of the resonator 1600 may bechanged by adjusting the distance h.

In some instances, a controller may be provided that is configured tocontrol the matcher 1630 which generates and transmits a control signalto the matcher 1630 directing the matcher to change its physical shapeso that the impedance of the resonator may be adjusted. For example, thedistance h between the conductor 1631 of the matcher 1630 and the groundconducting portion 1613 may be increased or decreased based on thecontrol signal. The controller may generate the control signal based onvarious factors.

As illustrated in FIG. 16, the matcher 1630 may be configured as apassive element such as the conductor 1631, for example. Of course, inothers embodiments, the matcher 1630 may be configured as an activeelement such as a diode, a transistor, or the like. If the activeelement is included in the matcher 1630, the active element may bedriven based on the control signal generated by the controller, and theimpedance of the resonator 1600 may be adjusted based on the controlsignal. For example, when the active element is a diode included in thematcher 1630, the impedance of the resonator 1600 may be adjusteddepending on whether the diode is in an on state or in an off state.

In some instances, a magnetic core may be further provided to passthrough the MNG resonator 1600. The magnetic core may perform a functionof increasing a power transmission distance.

FIG. 17 is an illustration of a resonator 1700 having athree-dimensional (3D) structure.

Referring to FIG. 17, the resonator 1700 having the 3D structure mayinclude a transmission line and a capacitor 1720. The transmission linemay include a first signal conducting portion 1711, a second signalconducting portion 1712, and a ground conducting portion 1713. Thecapacitor 1720 may be inserted, for instance, in series between thefirst signal conducting portion 1711 and the second signal conductingportion 1712 of the transmission link such that an electric field may beconfined within the capacitor 1720.

As illustrated in FIG. 17, the resonator 1700 may have a generally 3Dstructure. The transmission line may include the first signal conductingportion 1711 and the second signal conducting portion 1712 in an upperportion of the resonator 1700, and may include the ground conductingportion 1713 in a lower portion of the resonator 1700. The first signalconducting portion 1711 and the second signal conducting portion 1712may be disposed to face the ground conducting portion 1713. In thisarrangement, current may flow in an x direction through the first signalconducting portion 1711 and the second signal conducting portion 1712.Due to the current, a magnetic field H(W) may be formed in a −ydirection. However, it will be appreciated that the magnetic field H(W)might also be formed in the opposite direction (e.g., a +y direction) inother implementations.

In one or more embodiments, one end of the first signal conductingportion 1711 may be electrically connected (i.e., shorted) to theconductor 1742, and another end of the first signal conducting portion1711 may be connected to the capacitor 1720. One end of the secondsignal conducting portion 1712 may be grounded to the conductor 1741,and another end of the second signal conducting portion 1712 may beconnected to the capacitor 1720. Accordingly, the first signalconducting portion 1711, the second signal conducting portion 1712, theground conducting portion 1713, and the conductors 1741 and 1742 may beconnected to each other, whereby the resonator 1700 may have anelectrically closed-loop structure. As illustrated in FIG. 17, thecapacitor 1720 may be inserted or otherwise positioned between the firstsignal conducting portion 1711 and the second signal conducting portion1712. For example, the capacitor 1720 may be inserted into a spacebetween the first signal conducting portion 1711 and the second signalconducting portion 1712. The capacitor 1720 may include, for example, alumped element, a distributed element, and the like. In oneimplementation, a distributed capacitor having the shape of thedistributed element may include zigzagged conductor lines and adielectric material having a relatively high permittivity positionedbetween the zigzagged conductor lines.

When the capacitor 1720 is inserted into the transmission line, theresonator 1700 may have a property of a metamaterial, in some instances,as discussed above.

For example, when a capacitance of the capacitor is a lumped element,the resonator 1700 may have the characteristic of the metamaterial. Whenthe resonator 1700 has a negative magnetic permeability by appropriatelyadjusting the capacitance of the capacitor 1720, the resonator 1700 mayalso be referred to as an MNG resonator. Various criteria may be appliedto determine the capacitance of the capacitor 1720. For example, thevarious criteria may include one or more of the following: a criterionto enable the resonator 1700 to have the characteristic of themetamaterial, a criterion to enable the resonator 1700 to have anegative magnetic permeability in a target frequency, a criterion toenable the resonator 1700 to have a zeroth order resonancecharacteristic in the target frequency, or the like. Based on at leastone criterion among the aforementioned criteria, the capacitance of thecapacitor 1720 may be determined

The resonator 1700, also referred to as the MNG resonator 1700, may havea zeroth order resonance characteristic (i.e., having, as a resonancefrequency, a frequency when a propagation constant is “0”). If theresonator 1700 has a zeroth order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 1700. Thus, by appropriately designing thecapacitor 1720, the MNG resonator 1700 may sufficiently change theresonance frequency without significantly changing the physical size ofthe MNG resonator 1700.

Referring to the MNG resonator 1700 of FIG. 17, in a near field, theelectric field may be concentrated on the capacitor 1720 inserted intothe transmission line. Accordingly, due to the capacitor 1720, themagnetic field may become dominant in the near field. And, since the MNGresonator 1700 having the zeroth-order resonance characteristic may havecharacteristics similar to a magnetic dipole, the magnetic field maybecome dominant in the near field. A relatively small amount of theelectric field formed due to the insertion of the capacitor 1720 may beconcentrated on the capacitor 1720 and thus, the magnetic field maybecome further dominant

Also, the MNG resonator 1700 may include the matcher 1730 to be used inimpedance matching. The matcher 1730 may be configured to appropriatelyadjust the strength of magnetic field of the MNG resonator 1700. Theimpedance of the MNG resonator 1700 may be determined by the matcher1730. In one or more embodiments, current may flow in the MNG resonator1700 via a connector 1740, or may flow out from the MNG resonator 1700via the connector 1740. And the connector 1740 may be connected to theground conducting portion 1713 or the matcher 1730.

As illustrated in FIG. 17, the matcher 1730 may be positioned within theloop formed by the loop structure of the resonator 1700. The matcher1730 may be configured to adjust the impedance of the resonator 1700 bychanging the physical shape of the matcher 1730. For example, thematcher 1730 may include the conductor 1731 to be used in the impedancematching in a location separate from the ground conducting portion 1713by a distance h. The impedance of the resonator 1700 may be changed byadjusting the distance h.

In some implementations, a controller may be provided to control thematcher 1730. In this case, the matcher 1730 may change the physicalshape of the matcher 1730 based on a control signal generated by thecontroller. For example, the distance h between the conductor 1731 ofthe matcher 1730 and the ground conducting portion 1713 may be increasedor decreased based on the control signal. Accordingly, the physicalshape of the matcher 1730 may be changed such that the impedance of theresonator 1700 may be adjusted. The distance h between the conductor1731 of the matcher 1730 and the ground conducting portion 1713 may beadjusted using a variety of schemes. For example, one or more conductorsmay be included in the matcher 1730 and the distance h may be adjustedby adaptively activating one of the conductors. Alternatively oradditionally, the distance h may be adjusted by adjusting the physicallocation of the conductor 1731 up and down. For instance, the distance hmay be controlled based on the control signal of the controller. Thecontroller may generate the control signal using various factors. Asillustrated in FIG. 17, the matcher 1730 may be configured as a passiveelement such as the conductor 1731, for instance. Of course, in otherembodiments, the matcher 1730 may be configured as an active elementsuch as a diode, a transistor, or the like. If the active element isincluded in the matcher 1730, the active element may be driven based onthe control signal generated by the controller, and the impedance of theresonator 1700 may be adjusted based on the control signal. For example,if the active element is a diode included in the matcher 1730, theimpedance of the resonator 1700 may be adjusted depending on whether thediode is in an ON state or in an OFF state.

In some implementations, a magnetic core may be further provided to passthrough the resonator 1700 configured as the MNG resonator. The magneticcore may increase the power transmission distance.

FIG. 18 illustrates a resonator 1800 for a wireless power transmissionconfigured as a bulky type.

As used herein, the term “bulky type” may refer to a seamless connectionconnecting at least two parts in an integrated form.

Referring to FIG. 18, a first signal conducting portion 1811 and aconductor 1842 may be integrally formed, rather than being separatelymanufactured and being connected to each other. Similarly, a secondsignal conducting portion 1812 and a conductor 1841 may also beintegrally manufactured.

When the second signal conducting portion 1812 and the conductor 1841are separately manufactured and then are connected to each other, a lossof conduction may occur due to a seam 1850. Thus, in someimplementations, the second signal conducting portion 1812 and theconductor 1841 may be connected to each other without using a separateseam (i.e., seamlessly connected to each other). Accordingly, it maypossible to decrease a conductor loss caused by the seam 1850. Forinstance, the second signal conducting portion 1812 and a groundconducting portion 1813 may be seamlessly and integrally manufactured.Similarly, the first signal conducting portion 1811, the conductor 1842and the ground conducting portion 1813 may be seamlessly and integrallymanufactured.

A matcher 1830 may be provided that is similarly constructed asdescribed herein in one or more embodiments. FIG. 19 illustrates aresonator 1900 for a wireless power transmission, configured as a hollowtype.

Referring to FIG. 19, each of a first signal conducting portion 1911, asecond signal conducting portion 1912, a ground conducting portion 1913,and conductors 1941 and 1942 of the resonator 1900 configured as thehollow type structure. As used herein the term “hollow type” refers to aconfiguration that may include an empty space inside.

For a given resonance frequency, an active current may be modeled toflow in only a portion of the first signal conducting portion 1911instead of all of the first signal conducting portion 1911, a portion ofthe second signal conducting portion 1912 instead of all of the secondsignal conducting portion 1912, a portion of the ground conductingportion 1913 instead of all of the ground conducting portion 1913, andportions of the conductors 1941 and 1942 instead of all of theconductors 1941 and 1942. When a depth of each of the first signalconducting portion 1911, the second signal conducting portion 1912, theground conducting portion 1913, and the conductors 1941 and 1942 issignificantly deeper than a corresponding skin depth in thepredetermined resonance frequency, such a structure may be ineffective.The significantly deeper depth may, however, increase a weight ormanufacturing costs of the resonator 1900 in some instances.

Accordingly, for the given resonance frequency, the depth of each of thefirst signal conducting portion 1911, the second signal conductingportion 1912, the ground conducting portion 1913, and the conductors1941 and 1942 may be appropriately determined based on the correspondingskin depth of each of the first signal conducting portion 1911, thesecond signal conducting portion 1912, the ground conducting portion1913, and the conductors 1941 and 1942. When one or more of the firstsignal conducting portion 1911, the second signal conducting portion1912, the ground conducting portion 1913, and the conductors 1941 and1942 have an appropriate depth deeper than a corresponding skin depth,the resonator 1900 may be manufactured to be lighter, and manufacturingcosts of the resonator 1900 may also decrease.

For example, as illustrated in FIG. 19, the depth of the second signalconducting portion 1912 (as further illustrated in the enlarged viewregion 1960 indicated by a circle) may be determined as “d” mm, and dmay be determined according to

$\begin{matrix}{d = {\frac{1}{\sqrt{\pi\; f\;{\mu\sigma}}}.}} & \;\end{matrix}$Here, f denotes a frequency, μ denotes a magnetic permeability, and σdenotes a conductor constant. In one implementation, when the firstsignal conducting portion 1911, the second signal conducting portion1912, the ground conducting portion 1913, and the conductors 1941 and1942 are made of a copper and they may have a conductivity of 5.8×10⁷siemens per meter (S·m⁻¹), the skin depth may be about 0.6 mm withrespect to 10 kHz of the resonance frequency, and the skin depth may beabout 0.006 mm with respect to 100 MHz of the resonance frequency.

A capacitor 1920 and a matcher 1930 may be provided that are similarlyconstructed as described herein in one or more embodiments.

FIG. 20 illustrates a resonator 2000 for a wireless power transmissionusing a parallel-sheet configuration.

Referring to FIG. 20, the parallel-sheet configuration may be applicableto each of a first signal conducting portion 2011 and a second signalconducting portion 2012 included in the resonator 2000.

The first signal conducting portion 2011 and/or the second signalconducting portion 2012 may not be perfect conductors, and thus may havean inherent resistance. Due to this resistance, an ohmic loss may occur.The ohmic loss may decrease a Q-factor and may also decrease a couplingeffect.

By applying the parallel-sheet configuration to each of the first signalconducting portion 2011 and the second signal conducting portion 2012,it may be possible to decrease the ohmic loss, and to increase theQ-factor and the coupling effect. Referring to the enlarged view portion2070 (indicated by a circle in FIG. 20), each of the first signalconducting portion 2011 and the second signal conducting portion 2012may include a plurality of conductor lines. The plurality of conductorlines may be disposed in parallel, and may be electrically connected(i.e., shorted) at an end portion of each of the first signal conductingportion 2011 and the second signal conducting portion 2012.

When the parallel-sheet configuration is applied to one or both of thefirst signal conducting portion 2011 and the second signal conductingportion 2012, the plurality of conductor lines may be disposed inparallel. Accordingly, the sum of resistances having the conductor linesmay decrease. Consequently, the resistance loss may decrease, and theQ-factor and the coupling effect may increase.

A capacitor 2020 and a matcher 2030 positioned on the ground conductingportion 2013 may be provided that are similarly constructed as describedherein in one or more embodiments.

FIG. 21 illustrates a resonator 2100 for a wireless power transmissionincluding a distributed capacitor.

Referring to FIG. 21, a capacitor 2120 included in the resonator 2100 isconfigured for the wireless power transmission. A capacitor used as alumped element may have a relatively high equivalent series resistance(ESR). A variety of schemes have been proposed to decrease the ESRcontained in the capacitor of the lumped element. According to anembodiment, by using the capacitor 2120 as a distributed element, it maybe possible to decrease the ESR. As will be appreciated, a loss causedby the ESR may decrease a Q-factor and a coupling effect.

As illustrated in FIG. 21, the capacitor 2120 may be configured as aconductive line having the zigzagged structure.

By employing the capacitor 2120 as the distributed element, it may bepossible to decrease the loss occurring due to the ESR in someinstances. In addition, by disposing a plurality of capacitors as lumpedelements, it is possible to decrease the loss occurring due to the ESR.Since a resistance of the capacitors as the lumped elements decreasesthrough a parallel connection, active resistances of parallel-connectedcapacitors as the lumped elements may also decrease, whereby the lossoccurring due to the ESR may decrease. For example, by employing tencapacitors of 1 pF each instead of using a single capacitor of 10 pF, itmay be possible to decrease the loss occurring due to the ESR in someinstances.

FIG. 22A illustrates one embodiment of the matcher 1630 used in theresonator 1600 illustrated in FIG. 16, and FIG. 22B illustrates anexample of the matcher 1730 used in the resonator 1700 illustrated inFIG. 17.

FIG. 22A illustrates a portion of the resonator 1600 of FIG. 16including the matcher 1630, and FIG. 22B illustrates a portion of theresonator 1700 of FIG. 17 including the matcher 1730.

Referring to FIG. 22A, the matcher 1630 may include the conductor 1631,a conductor 1632, and a conductor 1633. The conductors 1632 and 1633 maybe connected to the ground conducting portion 1613 and the conductor1631. The impedance of the 2D resonator may be determined based on adistance h between the conductor 1631 and the ground conducting portion1613. The distance h between the conductor 1631 and the groundconducting portion 1613 may be controlled by the controller. Thedistance h between the conductor 1631 and the ground conducting portion1613 may be adjusted using a variety of schemes. For example, thevariety of schemes may include one or more of the following: a scheme ofadjusting the distance h by adaptively activating one of the conductors1631, 1632, and 1633, a scheme of adjusting the physical location of theconductor 1631 up and down, and/or the like.

Referring to FIG. 22B, the matcher 1730 may include the conductor 1731,a conductor 1732, a conductor 1733 and conductors 1741 and 1742. Theconductors 1732 and 1733 may be connected to the ground conductingportion 1713 and the conductor 1731. The impedance of the 3D resonatormay be determined based on a distance h between the conductor 1731 andthe ground conducting portion 1713. The distance h between the conductor1731 and the ground conducting portion 1713 may be controlled by thecontroller, for example. Similar to the matcher 1630 illustrated in FIG.22A, in the matcher 1730, the distance h between the conductor 1731 andthe ground conducting portion 1713 may be adjusted using a variety ofschemes. For example, the variety of schemes may include one or more ofthe following: a scheme of adjusting the distance h by adaptivelyactivating one of the conductors 1731, 1732, and 1733, a scheme ofadjusting the physical location of the conductor 1731 up and down, andthe like.

In some implementations, the matcher may include an active element.Thus, a scheme of adjusting an impedance of a resonator using the activeelement may be similar to the examples described above. For example, theimpedance of the resonator may be adjusted by changing a path of acurrent flowing through the matcher using the active element.

FIG. 23 illustrates one equivalent circuit of the resonator 1600 of FIG.16.

The resonator 1600 of FIG. 16 used in wireless power transmission may bemodeled to the equivalent circuit of FIG. 23. In the equivalent circuitdepicted in FIG. 23, L_(R) denotes an inductance of the powertransmission line, C_(L) denotes the capacitor 1620 that is inserted ina form of a lumped element in the middle of the power transmission line,and C_(R) denotes a capacitance between the power transmissions and/orground of FIG. 16.

In some instances, the resonator 1600 may have a zeroth resonancecharacteristic. For example, when a propagation constant is “0”, theresonator 1600 may be assumed to have ω_(MZR) as a resonance frequency.The resonance frequency ω_(MZR) may be expressed by Equation 1.

$\begin{matrix}{\omega_{MZR} = \frac{1}{\sqrt{L_{R}C_{L}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1, MZR denotes a Mu zero resonator.

Referring to Equation 1, the resonance frequency ω_(MZR) of theresonator 1600 may be determined by L_(R)/C_(L). A physical size of theresonator 1600 and the resonance frequency ω_(MZR) may be independentwith respect to each other. Since the physical sizes are independentwith respect to each other, the physical size of the resonator 1600 maybe sufficiently reduced.

The units described herein may be implemented using hardware components,software components, or a combination thereof. For example, a processingdevice may be implemented using one or more general-purpose or specialpurpose computers, such as, for example, a processor, a controller andan arithmetic logic unit, a digital signal processor, a microcomputer, afield programmable array, a programmable logic unit, a microprocessor orany other device capable of responding to and executing instructions ina defined manner The processing device may run an operating system (OS)and one or more software applications that run on the OS. The processingdevice also may access, store, manipulate, process, and create data inresponse to execution of the software. For purpose of simplicity, thedescription of a processing device is used as singular; however, oneskilled in the art will appreciated that a processing device may includemultiple processing elements and multiple types of processing elements.For example, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, for independently orcollectively instructing or configuring the processing device to operateas desired. Software and data may be embodied permanently or temporarilyin any type of machine, component, physical or virtual equipment,computer storage medium or device, or in a propagated signal wavecapable of providing instructions or data to or being interpreted by theprocessing device. The software also may be distributed over networkcoupled computer systems so that the software is stored and executed ina distributed fashion. In particular, the software and data may bestored by one or more computer readable recording mediums. The computerreadable recording medium may include any data storage device that canstore data which can be thereafter read by a computer system orprocessing device. Examples of the computer readable recording mediuminclude read-only memory (ROM), random-access memory (RAM), CD-ROMs,magnetic tapes, floppy disks, optical data storage devices. Also,functional programs, codes, and code segments for accomplishing theexample embodiments disclosed herein can be easily construed byprogrammers skilled in the art to which the embodiments pertain based onand using the flow diagrams and block diagrams of the figures and theircorresponding descriptions as provided herein.

A number of examples have been described above. Nevertheless, it shouldbe understood that various modifications may be made. For example,suitable results may be achieved if the described techniques areperformed in a different order and/or if components in a describedsystem, architecture, device, or circuit are combined in a differentmanner and/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are within the scope ofthe following claims.

What is claimed is:
 1. A method, executed by a power receiver, of controlling wireless power reception, the method comprising: receiving, from a power transmitter, a first wireless power in each time interval among a plurality of time intervals, wherein a resonance frequency corresponding to the first wireless power received in each time interval is different from resonance frequencies in all other time intervals among the plurality of time intervals; transmitting, to the power transmitter, information about an amount of the first wireless power received in each time interval; and receiving, from the power transmitter, a second wireless power having a resonance frequency with a highest power transmission efficiency, selected based on the information about the amount of the first wireless power received in each time interval; charging the power receiver with the received second wireless power.
 2. The method of claim 1, further comprising; transmitting a report message comprising a charging status of the power receiver and an identifier of the power receiver.
 3. The method of claim 2, further comprising: determining whether a charging of the power receiver is completed; and in response to a completion of the charging of the power receiver, notifying the power transmitter of the completion of the charging of the power receiver.
 4. The method of claim 1, wherein the resonance frequency corresponding to the first wireless power in each time interval is determined by any of: scanning a frequency characteristic of a reflected wave, based on a channel of a predetermined width, or is randomly in a predetermined bandwidth.
 5. A method, executed by a power transmitter, of controlling wireless power transmission, the method comprising: transmitting, to a power receiver, a first wireless power in each time interval among a plurality of time intervals, wherein a resonance frequency corresponding to the first wireless power in each time interval is different from resonance frequencies in all other time intervals among the plurality of time intervals; receiving, from the power receiver, information about an amount of the first wireless power received by the power receiver in each time interval; and transmitting, to the power receiver, a second wireless power having a resonance frequency with a highest power transmission efficiency, selected based on the information about the amount of the first wireless power received in each time interval.
 6. The method of claim 5, further comprising: receiving a report message comprising a charging status of the power receiver and an identifier of the power receiver.
 7. The method of claim 6, further comprising: in response to not receiving the report message from the power receiver within the predetermined period of time, determining that the power receiver does not exist.
 8. The method of claim 5, further comprising: receiving a notification indicating the completion of the charging of the power receiver.
 9. The method of claim 5, wherein the resonance frequency corresponding to the wireless power in each time interval is determined by any of: scanning a frequency characteristic of a reflected wave, based on a channel of a predetermined width, or randomly in a predetermined bandwidth.
 10. A power receiver comprising: a target resonator configured to receive a wireless power transmitted from a power transmitter; a communication unit configured to communicate with the power transmitter; and a controller configured to: control the target resonator to receive a first wireless power transmitted from the power transmitter in each time interval among a plurality of time intervals, wherein a resonance frequency corresponding to the first wireless power received in each time interval is different from resonance frequencies in all other time intervals among the plurality of time intervals, control the communication unit to transmit, to the power transmitter, information about an amount of the first wireless power received in each time interval, control the target resonator to receive a second wireless power transmitted from the power transmitter, the second wireless power having a resonance frequency having a highest power transmission efficiency, selected based on the information about the amount of the first wireless power received in each time interval, and control to charge the power receiver with the received second wireless power.
 11. The power receiver of claim 10, wherein the controller is further configured to control the communication unit to transmit a report message comprising a charging status of the power receiver and an identifier of the power receiver.
 12. The power receiver of claim 11, wherein the controller is further configured to control to determine whether a charging of the power receiver is completed, and to notify the power transmitter of the completion of the charging of the power receiver based on the completion of the charging of the power receiver.
 13. The power receiver of claim 10, wherein the resonance frequency corresponding to the first wireless power in each time interval is determined by any of: scanning a frequency characteristic of a reflected wave, based on a channel of a predetermined width, or is randomly in a predetermined bandwidth.
 14. A power transmitter comprising: a source resonator configured to transmit a wireless power to a power receiver; a communication unit configured to communicate with the power receiver; and a controller configured to: control the source resonator to transmit, to the power receiver, a first wireless power in each time interval among a plurality of time intervals, wherein a resonance frequency corresponding to the first wireless power in each time interval is different from resonance frequencies in all other time intervals among the plurality of time intervals, control the communication unit to receive, from the power receiver, information about an amount of the first wireless power received by the power receiver in each time interval, control to generate a second wireless power having a resonance frequency having a highest power transmission efficiency, selected based on the received information about the amount of the first wireless power received in each time interval, and control the source resonator to transmit the second wireless power to the power receiver.
 15. The power transmitter of claim 14, wherein the controller is further configured to control to receive a report message from the power receiver within a predetermined period of time, the report message comprising a charging status of the power receiver and an identifier of the power receiver.
 16. The power transmitter of claim 15, wherein the controller is further configured to control to determine that the power receiver does not exist based on not receiving the report message from the power receiver within the predetermined period of time.
 17. The power transmitter of claim 14, wherein the controller is further configured to control to receive a notification indicating a completion of the charging of the power receiver.
 18. The power transmitter of claim 17, wherein the resonance frequency corresponding to the wireless power in each time interval is determined by any of: scanning a frequency characteristic of a reflected wave, based on a channel of a predetermined width, or randomly in a predetermined bandwidth. 